|Spoiler Inside: Solution to Puzzle||SelectShow>|
Each of the three cookie ingredients is in three combinations: the ingredient is the only one and the two combinations of it and one of the other ingredients.
Since each cookie ingredient is in eight cookies, the only-one combinations must each be 8 minus the two ingredient combinations for an ingredient. This gives chocolate chip: 3, raisins 1: cinnamon: 2. Adding up, there is a total of fifteen cookies. You got shorted by nine cookies.